The disclosure of U.S. Provisional Application No. 61/491,060, filed May 27, 2011, is hereby incorporated herein in its entirety by reference.
Sickles typically including cutter bars supporting a row of knives, have been used to cut plants, including, but not limited to, hay, grasses, small grains and the like, for many years. The knives are composed of a plurality of knife or sickle sections which are mounted in side by side relation forming an elongate metal knife assembly. The elongate knife assembly is normally supported so as to slide longitudinally along an elongate stationary bar that has forwardly projecting, spaced apart guards bolted to a structural beam. The knife assembly moves back and forth in a reciprocating movement to move the knives relative to the guards so that the leading knife edges of the knives cross over the guards or through slots in the guards. This produces a shearing or cutting action which severs plant stems and stalks or other material captured between the knives and the guards.
In a harvesting machine, such as a combine or windrower, the knife assembly and stationary bar are typically supported in connection with a cutting head or header, and are oriented so as to extend sidewardly along a forward edge portion of structure such as a floor or pan of the header, hereinafter sometimes referred to generally as the floor. The floor or pan defines the lower periphery of a cut crop or plant flow area, which can include conveying apparatus, such as one or more augers or belts, operable in cooperation with a reel in machines so equipped, for conveying the cut plant material and crops, for instance, to a feeder inlet of a combine or windrow forming apparatus of a windrower.
A knife assembly, which will weigh from 35 to 38 pounds for a typical 20 foot wide header, typically must accelerate and decelerate two times per cycle as a result of the reciprocating movement. A typical speed for the knife assembly is up to about 16 hertz or cycles per second. Thus, it can be seen, the reciprocating motion at a high cycle per second generates high acceleration values and high deceleration values that in turn generate high forces on the structural components. Other damage that can occur includes dulled, chipped, and broken knife sections, that will result in unsatisfactory plant cutting, necessitating replacement of the damaged sections.
The knife sections and supporting structure are also subject to general wear, e.g., from friction, which can be accelerated by use in abrasive environments such as dusty areas and some plant varieties. As a result, the vertical height or position of the knife assembly can gradually lower relative to the drive mechanism which reciprocatingly propels it sidewardly. And, when changing worn components such as knife sections, the new knife sections may be thicker, which can change the vertical relationship between the top of the knife assembly and the drive mechanism. Also, some stationary bars may have some vertical flexibility, which can result in variances between the heights of the knife assembly and drive during operation, for instance, resulting from passage of the sickle over uneven terrain.
Known reciprocating sickle drives include, but are not limited to, an eccentric shaft on a rotating hub, a wobble drive, or a similar well known commercially available device. Such drives are typically located at the sides of the header, so as to drive the knife assembly from the end. Reference in this regard, the modern side located epicyclical sickle drive of Regier et al., U.S. Pat. No. 7,121,074 B1 issued Oct. 17, 2006, which illustrates a representative simple end connection to a sickle. An end connection is advantageous as it allows easy and quick disconnection of the drive from the knife assembly and removal and replacement thereof, it does not interfere with access to individual knife sections for removal and replacement, and it allows substantial flexibility and variance between the relative locations of the drive mechanism and the sickle.
Disadvantages of the side drive location include that the header must include significant frame structure for supporting the drive and to withstand forces and vibrations generated thereby. The end structure or crop divider at the end of the header must also be relatively wide, to accommodate the drive and to direct adjacent standing crops therepast, and increasing the possibility of accidentally pushing down adjacent standing crops. Additionally, for headers utilizing two drives located on opposite sides of the header, it is usually desired to time the operation of the drives such that the forces and vibrations generated by the respective drives cancel one another. This typically involves relatively long mechanical drive lines connecting the two drives together, which is disadvantageous as it adds weight, cost and complexity.
Driving a knife assembly or assemblies of a header from a more central location, such as the center of the header, is desirable as it provides several advantages compared to a side location. As a result, center drive mechanisms have been developed. Reference in this regard, Priepke U.S. Pat. Nos. 7,810,304; 7,805,919; 7,730,709; 7,520,118; and 7,401,458, and Bich U.S. Pat. No. 8,011,272 which disclose a family of vertically compact sickle drive or drives incorporated in or below a header floor, which overcome many of the disadvantages and shortcomings discussed above in regard to side drives. However, locating the sickle drive mechanism in or below the header floor can still result in the apparatus connecting the drive or drives with the knife assembly or assemblies being in the path of the cut plant material moving rearwardly past the sickle, so as to interfere with and/or split the material flow and even cause some plowing and accumulation of the cut plant material in front of the connecting apparatus. Therefore, it would be desirable to minimize such interference and splitting of the material flow.
Reference also Bich et al. U.S. Pat. No. 8,151,547 which discloses a knife arm assembly, configured for attachment to a center drive, which has the shortcomings of a knife head requiring an intermediary member for attachment to the knife, and removal and replacement of the knife pin of which connecting the knife head to the knife arm requires removal of the entire knife head from the sickle knife.
It would also be desirable to have a manner of adjusting or compensating for any differences or variances between the height of the drive mechanism or mechanisms and the knife assembly or assemblies, for accommodating manufacturing and assembly variations, tolerances, and wear, and to avoid increased friction and binding that can increase wear on both the sickle and drive and increase power consumption.
As another consideration, when individual or groups of knife sections are worn beyond their useful life, or are broken or damaged, so as to require removal and replacement, it would be desirable to have a manner of replacing them quickly and easily, particularly in the field during plant cutting operations, to minimize downtime and effects on production.
Still further, it would be desirable to have the ability to remove and replace the knife pin of a knife head, without having to remove the entire knife head from the sickle knife for service.
Therefore, what is sought is apparatus for connection of a sickle drive to the knife of a sickle, adapted for use along the length of a sickle, e.g., at a more central location on a header, which provides ease of removal, service and replacement, minimizes interruption and splitting of plant material flow, is vertically self-adjusting, and provides one or more of the other features, while overcoming one or more of the shortcomings and limitations, set forth above.